Fluid loss control additives for use in fracturing subterranean formations

ABSTRACT

The present invention relates to subterranean fracturing operations, and more particularly to fracturing fluids that include an improved fluid loss control additive, and methods of using such fracturing fluids in fracturing subterranean formations. An example of a method of the present invention is a method of fracturing a subterranean formation. Another example of a method of the present invention is a method of controlling loss of a fracturing fluid during fracturing of a subterranean formation. Another example of a method of the present invention is a method of minimizing fluid loss in a subterranean formation. An example of a composition of the present invention is a pad fluid for use in fracturing a subterranean formation. Another example of a composition of the present invention is a fluid loss control additive for use in a fracturing fluid to be placed in a subterranean formation.

BACKGROUND OF THE INVENTION

The present invention relates to subterranean fracturing operations, andmore particularly to fracturing fluids comprising an improved fluid losscontrol additive, and methods of using such fracturing fluids infracturing subterranean formations.

Hydrocarbon-producing wells often are stimulated by hydraulic fracturingoperations, wherein a fluid (often referred to as a “pad” fluid) isintroduced into a portion of a subterranean formation at a hydraulicpressure sufficient to create or enhance at least one fracture therein.After the placement of the pad fluid, one or more subsequent fluids,laden with proppant particles, may be placed in the zone so that theproppant particles may be placed in the resultant fractures to maintainthe integrity of the fractures (after the hydraulic pressure isreleased), thereby forming conductive channels within the formationthrough which hydrocarbons can flow. Once at least one fracture has beencreated and at least a portion of the proppant is substantially in placewithin the fracture, the viscosity of the pad fluid may be reduced, insome cases, to facilitate removal of the fracturing fluid from theformation.

In certain hydrocarbon-producing formations, much of the production maybe derived from natural fractures. These natural fractures may exist inthe reservoir prior to a fracturing operation, and, when contacted by aninduced fracture (e.g., a fracture formed or enhanced during afracturing treatment), may provide flow channels having a relativelyhigh conductivity that may improve hydrocarbon production from thereservoir.

In certain circumstances, a portion of a pad fluid and/or aproppant-laden fluid may be lost into the subterranean formation duringa fracturing operation. Conventional attempts to solve this problem haveincluded adding a conventional fluid loss control additive to the padfluid. Conventional fluid loss control additives generally compriserigid particles having a spheroid shape, and often are used mainly toprevent the loss of the pad fluid and the proppant-laden fluid(s) to theformation, e.g., loss of the pad fluid and the proppant-laden fluid(s)to the natural fractures in the formation. While conventional fluid losscontrol additives may be able to withstand the closure stress of aninduced fracture, they generally are not designed to withstand thestress exhibited by natural fractures in the formation. This may beparticularly problematic at an intersection between an induced fractureand a natural fracture, because a natural fracture that is intersectedby an induced fracture often will have a higher stress than the inducedfracture. Consequently, when conventional fluid loss control additivesenter, and potentially obstruct, natural fractures in the formation, theconventional fluid loss control additives often may be crushed withinthe natural fracture, which may be problematic because the crushedparticles may partially or completely restrict any production from thenatural fracture.

SUMMARY OF THE INVENTION

The present invention relates to subterranean fracturing operations, andmore particularly to fracturing fluids comprising an improved fluid losscontrol additive, and methods of using such fracturing fluids infracturing subterranean formations.

An example of a method of the present invention is a method offracturing a subterranean formation comprising the steps of: providing apad fluid comprising a base fluid and a fluid loss control additivecomprising a material that has a size in the range of from greater thanor equal to about 400 U.S. mesh to less than or equal to about 70 U.S.mesh and a compressive strength greater than the maximum stress of theformation; and contacting the formation with the pad fluid so as tocreate or enhance at least one fracture therein.

Another example of a method of the present invention is a method ofcontrolling loss of a fracturing fluid during fracturing of asubterranean formation, comprising adding a fluid loss control additiveto a pad fluid, wherein the fluid loss control additive comprises amaterial that has a size in the range of from greater than or equal toabout 400 U.S. mesh to less than or equal to about 70 U.S. mesh and acompressive strength greater than the maximum stress of the formation.

Another example of a method of the present invention is a method ofminimizing fluid loss in a subterranean formation comprising using afluid loss control additive to obstruct at least one pore throat in theformation, wherein the fluid loss control additive comprises a materialthat has a size in the range of from greater than or equal to about 400U.S. mesh to less than or equal to about 70 U.S. mesh and a compressivestrength greater than the maximum stress of the formation.

An example of a composition of the present invention is a pad fluid foruse in fracturing a subterranean formation comprising a fluid losscontrol additive comprising a material that has a size in the range offrom greater than or equal to about 400 U.S. mesh to less than or equalto about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation.

Another example of a composition of the present invention is a fluidloss control additive for use in a fracturing fluid to be placed in asubterranean formation comprising a material that has a size in therange of from greater than or equal to about 400 U.S. mesh to less thanor equal to about 70 U.S. mesh and a compressive strength greater thanthe maximum stress of the subterranean formation.

The features and advantages of the present invention will be readilyapparent to those skilled in the art upon a reading of the descriptionof the preferred embodiments, which follows.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention relates to subterranean fracturing operations, andmore particularly to fracturing fluids comprising an improved fluid losscontrol additive, and methods of using such fracturing fluids infracturing subterranean formations.

The fluid loss control additives of the present invention generallycomprise a material that has a size in the range of from greater than orequal to about 400 U.S. mesh to less than or equal to about 70 U.S. meshand a compressive strength greater than the maximum stress of asubterranean formation into which the fluid loss control additives maybe placed. In certain embodiments, the fluid loss control additives maycomprise a material having a size in the range of from greater than orequal to about 200 U.S. mesh to less than or equal to about 80 U.S. meshand a compressive strength greater than the maximum stress of asubterranean formation into which the fluid loss control additives maybe placed. Generally, the fluid loss control additives of the presentinvention will have a compressive strength greater than that of anatural fracture into which they may be placed. Generally, the fluidloss control additives of the present invention will have a compressivestrength greater than that demonstrated by sand. In certain embodiments,the fluid loss control additives of the present invention may have acompressive strength such that when exposed to 2,000 psi pressure, lessthan about 1.7% by weight of fines are generated. As referred to herein,the term “fines” will be understood to mean particles having a sizesmaller than about 400 U.S. mesh. In certain embodiments, the fluid losscontrol additives of the present invention may have a compressivestrength such that when exposed to 3,000 psi pressure, less than about2.8% by weight of fines are generated. In certain embodiments, the fluidloss control additives of the present invention may have a compressivestrength such that when exposed to 4,000 psi pressure, less than about4.4% by weight of fines are generated. In certain embodiments, the fluidloss control additives of the present invention may have a compressivestrength such that when exposed to 5,000 psi pressure, less than about7% by weight of fines are generated. Examples of suitable materials thatmay be used in the fluid loss control additives of the present inventionmay include, but are not limited to, bauxite or bauxite-based materials,and ceramics or ceramic-based materials. Suitable materials arecommercially available from Carboceramics, Inc., of Irving, Tex.; SintexMinerals & Services, Inc., of Houston, Tex.; and Norton-Alcoa Proppants,of Fort Smith, Ark. Examples of intermediate strength ceramic orceramic-based materials that may be suitable include, but are notlimited to, Econoprop®, Carbo Lite®, Carbo Prop®, Interprop®, Naplite®,and Valuprop®. Examples of high strength ceramic or ceramic-basedmaterials that may be suitable include, but are not limited to, CarboHSP®, Sintered Bauxite and SinterBall®. When a pad fluid comprising afluid loss control additive of the present invention is placed in asubterranean formation, any portion of the fluid loss control additivethat may be lost to the subterranean formation generally will besufficiently strong to resist being damaged or crushed by the stresspresent within the formation, which may facilitate improved conductivitythrough at least the portion of the formation in which the fluid losscontrol additive resides. Generally, the fluid loss control additive ispresent in the pad fluids of the present invention in an amountsufficient to provide a desired degree of fluid loss control. Moreparticularly, in certain embodiments, the fluid loss control additive ispresent in the pad fluids of the present invention in an amount in therange of from about 0.0006% to about 24% by weight of the pad fluid. Incertain embodiments, the fluid loss control additive is present in thepad fluids of the present invention in an amount in the range of fromabout 0.002% to about 6.0% by weight of the pad fluid.

The pad fluids of the present invention generally comprise a base fluid,and a fluid loss control additive. A variety of base fluids may beincluded in the pad fluids of the present invention. For example, thebase fluid may comprise water, acids, oils, or mixtures thereof.Examples of suitable acids include, but are not limited to, hydrochloricacid, acetic acid, formic acid, citric acid, or mixtures thereof. Incertain embodiments, the base fluid may further comprise a gas (e.g.,nitrogen, or carbon dioxide). Generally, the base fluid is present inthe pad fluids of the present invention in an amount in the range offrom about 30% to about 99% by weight of the pad fluid.

Optionally, the pad fluids of the present invention may comprise aviscosifier. Examples of suitable viscosifiers include, inter alia,biopolymers such as xanthan and succinoglycan, cellulose derivatives(e.g., hydroxyethylcellulose), and guar and its derivatives (e.g.,hydroxypropyl guar). In certain embodiments of the present invention,the viscosifier comprises guar. More particularly, the viscosifier maybe present in the pad fluids of the present invention in an amount inthe range of from about 0.01% to about 1.0% by weight of the pad fluid.In certain embodiments, the viscosifier may be present in the pad fluidin an amount in the range of from about 0.2% to about 0.6% by weight.

Optionally, the pad fluids of the present invention may compriseadditional additives as deemed appropriate by one skilled in the art,with the benefit of this disclosure. Examples of such additives include,but are not limited to, de-emulsifiers, surfactants, salts, crosslinkingagents, clay inhibitors, iron-control additives, breakers, bactericides,caustic, or the like. An example of a suitable de-emulsifier iscommercially available from Halliburton Energy Services, Inc., under thetrade name “LO-SURF 300.” An example of a suitable source of caustic iscommercially available from Halliburton Energy Services, Inc., under thetrade name “MO-67.” An example of a suitable crosslinking agent iscommercially available from Halliburton Energy Services, Inc., under thetrade name “CL-28M.” An example of a suitable breaker is commerciallyavailable from Halliburton Energy Services, Inc., under the trade name“VICON NF.” Examples of suitable bactericides are commercially availablefrom Halliburton Energy Services, Inc., under the trade names “BE-3S”and “BE-6.”

Generally, the pad fluids of the present invention, comprising a fluidloss control additive of the present invention, may be introduced to aportion of a subterranean formation at a pressure sufficient to createor enhance at least one fracture therein. Optionally, one or moresubsequent fluids that comprise proppant particles may be introduced tothe chosen portion of the formation so as to deposit at least a portionof the proppant particles in at least one fracture therein. Proppantparticles utilized in accordance with the present invention aregenerally of a size such that formation particulates that may migratewith produced fluids are prevented from being produced from thesubterranean zone. Any suitable proppant may be utilized in the one ormore subsequent fluids, including graded sand, bauxite, ceramicmaterials, glass materials, walnut hulls, polymer beads and the like.Generally, the proppant particles have a size in the range of from about2 to about 400 U.S. mesh. In some embodiments of the present invention,the proppant is graded sand having a particle size in the range of fromabout 10 to about 70 U.S. mesh. Particle size distribution ranges aregenerally one or more of 10-20 U.S. mesh, 20-40 U.S. mesh, 40-60 U.S.mesh or 50-70 U.S. mesh, depending on factors including, inter alia, theparticular size and distribution of formation particulates to bescreened out by the consolidated proppant particles, the permeability ofthe formation, and the cost of the proppant particles. Generally,proppant particles may be included in the one or more subsequent fluids,in an amount in the range of from about 4% to about 70% by weight.

An example of a method of the present invention is a method offracturing a subterranean formation comprising the steps of: providing apad fluid comprising a base fluid and a fluid loss control additivecomprising a material that has a size in the range of from greater thanor equal to about 400 U.S. mesh to less than or equal to about 70 U.S.mesh and a compressive strength greater than the maximum stress of theformation; and contacting the formation with the pad fluid so as tocreate or enhance at least one fracture therein. Additional steps couldinclude, inter alia, contacting the formation with one or moresubsequent fluids that comprise proppant particles so as to depositwithin the formation at least a portion of the proppant particles;“breaking” the pad fluid and/or the one or more subsequent fluids (e.g.,reducing the viscosity of the pad fluid and/or the one or moresubsequent fluids to a desired degree) with a suitable breaker;recovering at least a portion of the pad fluid from the subterraneanformation; and recovering at least a portion of the one or moresubsequent fluids from the subterranean formation.

Another example of a method of the present invention is a method ofcontrolling loss of a fracturing fluid during fracturing of asubterranean formation, comprising adding a fluid loss control additiveto a pad fluid, wherein the fluid loss control additive comprises amaterial that has a size in the range of from greater than or equal toabout 400 U.S. mesh to less than or equal to about 70 U.S. mesh and acompressive strength greater than the maximum stress of the formation.Another example of a method of the present invention is a method ofminimizing fluid loss in a subterranean formation comprising using afluid loss control additive to obstruct at least one pore throat in theformation, wherein the fluid loss control additive comprises a materialthat has a size in the range of from greater than or equal to about 400U.S. mesh to less than or equal to about 70 U.S. mesh and a compressivestrength greater than the maximum stress of the formation.

An example of a composition of the present invention is a pad fluid foruse in fracturing a subterranean formation comprising a fluid losscontrol additive comprising a material that has a size in the range offrom greater than or equal to about 400 U.S. mesh to less than or equalto about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation. In one embodiment, a pad fluid of thepresent invention may comprise: water, 1% potassium chloride by weight,0.05% LO-SURF 300 by weight, 0.15% of a fluid loss control additive ofthe present invention by weight, 0.2% guar by weight, 0.1% MO-67 byweight, 0.05% CL-28M by weight, 0.1% VICON NF by weight, 0.001% BE-3S byweight, and 0.001% BE-6 by weight.

Another example of a composition of the present invention is a fluidloss control additive for use in a fracturing fluid to be placed in asubterranean formation comprising a material that has a size in therange of from greater than or equal to about 400 U.S. mesh to less thanor equal to about 70 U.S. mesh and a compressive strength greater thanthe maximum stress of the subterranean formation.

Therefore, the present invention is well adapted to carry out theobjects and attain the ends and advantages mentioned as well as thosethat are inherent therein. While the invention has been depicted anddescribed by reference to exemplary embodiments of the invention, such areference does not imply a limitation on the invention, and no suchlimitation is to be inferred. The invention is capable of considerablemodification, alternation, and equivalents in form and function, as willoccur to those ordinarily skilled in the pertinent arts and having thebenefit of this disclosure. The depicted and described embodiments ofthe invention are exemplary only, and are not exhaustive of the scope ofthe invention. Consequently, the invention is intended to be limitedonly by the spirit and scope of the appended claims, giving fullcognizance to equivalents in all respects.

1. A method of fracturing a subterranean formation comprising the stepsof: providing a pad fluid comprising a base fluid and a fluid losscontrol additive comprising a material that has a size in the range offrom greater than or equal to about 400 U.S. mesh to less than or equalto about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation; and contacting the formation with thepad fluid so as to create or enhance at least one fracture therein. 2.The method of claim 1 further comprising the step of contacting theformation with one or more subsequent fluids that comprise proppantparticles so as to deposit at least a portion of the proppant particleswithin the formation.
 3. The method of claim 1 further comprising thestep of breaking the pad fluid with a breaker.
 4. The method of claim 1further comprising the step of breaking the one or more subsequentfluids with a breaker.
 5. The method of claim 1 further comprising thestep of recovering at least a portion of the pad fluid from thesubterranean formation.
 6. The method of claim 1 further comprising thestep of recovering at least a portion of the one or more subsequentfluids that comprise proppant particles from the subterranean formation.7. The method of claim 1 wherein the fluid loss control additivecomprises a material selected from the group consisting of: a ceramic, aceramic derivative, bauxite, or a bauxite derivative.
 8. The method ofclaim 1 wherein the fluid loss control additive is present in the padfluid in an amount in the range of from about 0.0006% to about 24% byweight of the pad fluid.
 9. The method of claim 1 wherein the fluid losscontrol additive has a size in the range of from greater than or equalto about 200 U.S. mesh to less than or equal to about 80 U.S. mesh. 10.The method of claim 1 wherein the fluid loss control additive has acompressive strength such that when exposed to a pressure of 2,000 psi,less than about 1.7% by weight of fines are generated.
 11. The method ofclaim 1 wherein the fluid loss control additive has a compressivestrength such that when exposed to a pressure of 3,000 psi, less thanabout 2.8% by weight of fines are generated.
 12. The method of claim 1wherein the fluid loss control additive has a compressive strength suchthat when exposed to a pressure of 4,000 psi, less than about 4.4% byweight of fines are generated.
 13. The method of claim 1 wherein thefluid loss control additive has a compressive strength such that whenexposed to a pressure of 5,000 psi, less than about 7% by weight offines are generated.
 14. The method of claim 1 wherein the base fluid iswater, oil, an acid, or a mixture thereof.
 15. The method of claim 1wherein the base fluid is present in the pad fluid in an amount in therange of from about 30% to about 99% by weight of the pad fluid.
 16. Themethod of claim 1 wherein the pad fluid further comprises a viscosifier.17. The method of claim 16 wherein the viscosifier further comprises abiopolymer, a cellulose derivative, or a mixture thereof.
 18. The methodof claim 17 wherein the biopolymer comprises xanthan, succinoglycan, ora mixture thereof.
 19. The method of claim 17 wherein the cellulosederivative comprises hydroxyethylcellulose, guar, a guar derivative, ora mixture thereof.
 20. The method of claim 19 wherein the guarderivative is hydroxypropyl guar.
 21. The method of claim 16 wherein theviscosifier is present in the pad fluid in an amount in the range offrom about 0.01% to about 1.0% by weight of the pad fluid.
 22. Themethod of claim 1 wherein the pad fluid further comprises ade-emulsifier, a salt, a crosslinking agent, a clay inhibitor, asurfactant, an iron-control additive, a breaker, a bactericide, caustic,or a mixture thereof.
 23. A method of controlling loss of a fracturingfluid during fracturing of a subterranean formation, comprising adding afluid loss control additive to a pad fluid, wherein the fluid losscontrol additive comprises a material that has a size in the range offrom greater than or equal to about 400 U.S. mesh to less than or equalto about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation.
 24. The method of claim 23 wherein thepad fluid comprises a viscosifier and a base fluid.
 25. The method ofclaim 23 wherein the fluid loss control additive comprises a materialselected from the group consisting of: bauxite, a bauxite derivative, aceramic, and a ceramic derivative.
 26. The method of claim 23 whereinthe fluid loss control additive is present in the pad fluid in an amountin the range of from about 0.0006% to about 24% by weight of the padfluid.
 27. The method of claim 23 wherein the fluid loss controladditive has a size in the range of from greater than or equal to about200 U.S. mesh to less than or equal to about 80 U.S. mesh.
 28. Themethod of claim 23 wherein the fluid loss control additive has acompressive strength such that when exposed to a pressure of 2,000 psi,less than about 1.7% by weight of fines are generated.
 29. The method ofclaim 23 wherein the fluid loss control additive has a compressivestrength such that when exposed to a pressure of 3,000 psi, less thanabout 2.8% by weight of fines are generated.
 30. The method of claim 23wherein the fluid loss control additive has a compressive strength suchthat when exposed to a pressure of 4,000 psi, less than about 4.4% byweight of fines are generated.
 31. The method of claim 23 wherein thefluid loss control additive has a compressive strength such that whenexposed to a pressure of 5,000 psi, less than about 7% by weight offines are generated.
 32. The method of claim 24 wherein the base fluidis water, oil, an acid, or a mixture thereof.
 33. The method of claim 24wherein the base fluid is present in the pad fluid in an amount in therange of from about 30% to about 99% by weight of the pad fluid.
 34. Themethod of claim 24 wherein the viscosifier comprises a biopolymer, acellulose derivative, or a mixture thereof.
 35. The method of claim 24wherein the viscosifier is present in the pad fluid in an amount in therange of from about 0.01% to about 1.0% by weight of the pad fluid. 36.The method of claim 23 wherein the pad fluid further comprises ade-emulsifier, a salt, a crosslinking agent, a clay inhibitor, aniron-control additive, a surfactant, a breaker, a bactericide, caustic,or a mixture thereof.
 37. A method of minimizing fluid loss in asubterranean formation comprising using a fluid loss control additive toobstruct at least one pore throat in the formation, wherein the fluidloss control additive comprises a material that has a size in the rangeof from greater than or equal to about 400 U.S. mesh to less than orequal to about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation.
 38. The method of claim 37 wherein thefluid loss control additive comprises a material selected from the groupconsisting of: bauxite, a bauxite derivative, a ceramic, and a ceramicderivative.
 39. The method of claim 37 wherein the step of using thefluid loss control additive to obstruct at least one pore throat in theformation comprises placing a pad fluid that comprises the fluid losscontrol additive in the subterranean formation, wherein the fluid losscontrol additive is present in the pad fluid in an amount in the rangeof from about 0.0006% to about 24% by weight of the pad fluid.
 40. Themethod of claim 37 wherein the fluid loss control additive has a size inthe range of from greater than or equal to about 200 U.S. mesh to lessthan or equal to about 80 U.S. mesh.
 41. The method of claim 37 whereinthe fluid loss control additive has a compressive strength such thatwhen exposed to a pressure of 2,000 psi, less than about 1.7% by weightof fines are generated.
 42. The method of claim 37 wherein the fluidloss control additive has a compressive strength such that when exposedto a pressure of 3,000 psi, less than about 2.8% by weight of fines aregenerated.
 43. The method of claim 37 wherein the fluid loss controladditive has a compressive strength such that when exposed to a pressureof 4,000 psi, less than about 4.4% by weight of fines are generated. 44.The method of claim 37 wherein the fluid loss control additive has acompressive strength such that when exposed to a pressure of 5,000 psi,less than about 7% by weight of fines are generated.
 45. A pad fluid foruse in fracturing a subterranean formation comprising a fluid losscontrol additive comprising a material that has a size in the range offrom greater than or equal to about 400 U.S. mesh to less than or equalto about 70 U.S. mesh and a compressive strength greater than themaximum stress of the formation.
 46. The pad fluid of claim 45 whereinthe pad fluid further comprises a base fluid.
 47. The pad fluid of claim46 wherein the base fluid comprises water, oil, an acid, or a mixturethereof.
 48. The pad fluid of claim 45 wherein the pad fluid furthercomprises a de-emulsifier, a salt, a crosslinking agent, a clayinhibitor, an iron-control additive, a surfactant, a breaker, abactericide, caustic, or a mixture thereof.
 49. The pad fluid of claim45 wherein the fluid loss control additive comprises a material selectedfrom the group consisting of: a ceramic, a ceramic derivative, bauxite,and a bauxite derivative.
 50. The pad fluid of claim 45 wherein thefluid loss control additive is present in the pad fluid in an amount inthe range of from about 0.0006% to about 24% by weight of the pad fluid.51. The pad fluid of claim 45 wherein the fluid loss control additivehas a size in the range of from greater than or equal to about 200 U.S.mesh to less than or equal to about 80 U.S. mesh.
 52. The pad fluid ofclaim 45 wherein the fluid loss control additive has a compressivestrength such that when exposed to a pressure of 2,000 psi, less thanabout 1.7% by weight of fines are generated.
 53. The pad fluid of claim45 wherein the fluid loss control additive has a compressive strengthsuch that when exposed to a pressure of 3,000 psi, less than about 2.8%by weight of fines are generated.
 54. The pad fluid of claim 45 whereinthe fluid loss control additive has a compressive strength such thatwhen exposed to a pressure of 4,000 psi, less than about 4.4% by weightof fines are generated.
 55. The pad fluid of claim 45 wherein the fluidloss control additive has a compressive strength such that when exposedto a pressure of 5,000 psi, less than about 7% by weight of fines aregenerated.
 56. The pad fluid of claim 45 wherein the base fluid ispresent in the pad fluid in an amount in the range of from about 30% toabout 99% by weight of the pad fluid.
 57. The pad fluid of claim 45,further comprising a viscosifier.
 58. The pad fluid of claim 57 whereinthe viscosifier comprises a biopolymer, a cellulose derivative, or amixture thereof.
 59. The pad fluid of claim 57 wherein the viscosifieris present in the pad fluid in an amount in the range of from about0.01% to about 1.0% by weight of the pad fluid.
 60. A fluid loss controladditive for use in a fracturing fluid to be placed in a subterraneanformation comprising a material that has a size in the range of fromgreater than or equal to about 400 U.S. mesh to less than or equal toabout 70 U.S. mesh and a compressive strength greater than the maximumstress of the subterranean formation.
 61. The fluid loss controladditive of claim 60 comprising a material selected from the groupconsisting of: a ceramic, a ceramic derivative, bauxite, and a bauxitederivative.
 62. The fluid loss control additive of claim 60 wherein thefluid loss control additive has a size in the range of from greater thanor equal to about 200 U.S. mesh to less than or equal to about 80 U.S.mesh.
 63. The fluid loss control additive of claim 60 wherein the fluidloss control additive has a compressive strength such that when exposedto a pressure of 2,000 psi, less than about 1.7% by weight of fines aregenerated.
 64. The fluid loss control additive of claim 60 wherein thefluid loss control additive has a compressive strength such that whenexposed to a pressure of 3,000 psi, less than about 2.8% by weight offines are generated.
 65. The fluid loss control additive of claim 60wherein the fluid loss control additive has a compressive strength suchthat when exposed to a pressure of 4,000 psi, less than about 4.4% byweight of fines are generated.
 66. The fluid loss control additive ofclaim 60 wherein the fluid loss control additive has a compressivestrength such that when exposed to a pressure of 5,000 psi, less thanabout 7% by weight of fines are generated.